Propagation By Layering

Press, Volume CVI, Issue 31178, 30 September 1966, Page 6

Propagation By Layering

There is a specialised form of propagation known as aerial, Chinese or Marcottage layering which is most useful in increasing rare and valuable plants. It is also used where normal layering methods cannot be used due to rigid branches, or where shooting or suckering is difficult. Oleander, lilac, wistaria, hibiscus, magnolias, rhododendrons, hamamellis, cytisus, cornus, viburnums, acers and mahonias are plants which lend themselves to this method. The job is usually carried out between October and November on last year’s growth and a shoot or stem at least 6in to 12in in length must be selected for the purpose.

Remove the lower leaves and make an incision to about half the thickness of the stem just below a node. The cut should then be deflected upwards for half an inch. Dust the wound with a growth promoting hormone such as Idoyl butric acid mixed with talc or nathalene acetic acid. Then pack and cover with spagnum moss to give a complete cover. The moss should be moistened and gently wrung out before applying and, if preferred, the hormone can be applied via the moss. Next wind a polythene sheet or film tightly around the moss, taping both ends tightly to make it completely airtight For this purpose the plastic adhesive tapes now generally available are ideal.

To allow for air interchange it is most important not to use polythene of greater thickness than four to six thousandths of an inch. A 9in square she it or film 3in to 4in wide wound around about 9in of stem will give sufficient ' coverage for one layering. Very little attention is rei quired thereafter, other than checking ties from time to time as there is no loss of ! water and none can enter, if : done until the fol- . lowing autumn. By that time the stem should have produced a good root system. The new plant i can be cut off and planted, the tape being removed only when thia is being done. The polythene is then removed with the least possible disturb- . ance.